The National Comorbidity Survey Replication (NCS-R) is a survey of the prevalence and correlates of mental disorders in the US that was carried out between February 2001 and April 2003. Interviews were administered face-to-face in the homes of respondents, who were selected from a nationally representative multi-stage clustered area probability sample of households. A total of 9,282 interviews were completed in the main survey and an additional 554 short non-response interviews were completed with initial non-respondents. This paper describes the main features of the NCS-R design and field procedures, including information on fieldwork organization and procedures, sample design, weighting and considerations in the use of design-based versus model-based estimation. Empirical information is presented on non-response bias, design effect, and the trade-off between bias and efficiency in minimizing total mean-squared error of estimates by trimming weights.

We previously reported on the cross-national epidemiology of ADHD from the first 10 countries in the WHO World Mental Health (WMH) Surveys. The current report expands those previous findings to the 20 nationally or regionally representative WMH surveys that have now collected data on adult ADHD. The Composite International Diagnostic Interview (CIDI) was administered to 26,744 respondents in these surveys in high-, upper-middle-, and low-/lower-middle-income countries (68.5% mean response rate). Current DSM-IV/CIDI adult ADHD prevalence averaged 2.8% across surveys and was higher in high (3.6%)- and upper-middle (3.0%)- than low-/lower-middle (1.4%)-income countries. Conditional prevalence of current ADHD averaged 57.0% among childhood cases and 41.1% among childhood subthreshold cases. Adult ADHD was significantly related to being male, previously married, and low education. Adult ADHD was highly comorbid with DSM-IV/CIDI anxiety, mood, behavior, and substance disorders and significantly associated with role impairments (days out of role, impaired cognition, and social interactions) when controlling for comorbidities. Treatment seeking was low in all countries and targeted largely to comorbid conditions rather than to ADHD. These results show that adult ADHD is prevalent, seriously impairing, and highly comorbid but vastly under-recognized and undertreated across countries and cultures.

Background Anxiety disorders are a major cause of burden of disease. Treatment gaps have been described, but a worldwide evaluation is lacking. We estimated, among individuals with a 12-month DSM-IV anxiety disorder in 21 countries, the proportion who: i) perceived a need for treatment; ii) received any treatment; and (iii) received possibly adequate treatment. Methods Data from 24 community surveys in 21 countries of the WMH surveys. DSM-IV mental disorders were assessed (WHO Composite International Diagnostic Interview, CIDI 3.0). DSM-IV included PTSD among anxiety disorders, while it is not considered so in the DSM-5. We asked if, in the previous 12 months, respondents felt they needed professional treatment and if they obtained professional treatment (specialized/general medical, complementary alternative medical, or non-medical professional) for “problems with emotions, nerves, mental health, or use of alcohol or drugs”. Possibly adequate treatment was defined as receiving pharmacotherapy (1+ months of medication and 4+ visits to a medical doctor) or psychotherapy, CAM or non-medical care (8+ visits). Results Of 51,547 respondents (response=71.3%), 9.8% had a 12-month DSM-IV anxiety disorder, 27.6% of whom received any treatment, and only 9.8% received possibly adequate treatment. 41.3% of those with 12-month anxiety perceived a need for care. Lower treatment levels were found for lower income countries. Conclusions Low levels of service use and a high proportion of those receiving services not meeting adequacy standards for anxiety disorders exist worldwide. Results suggest the need for improving recognition of anxiety disorders and the quality of treatment.

An overview is presented of the design and fi eld procedures of the US National Comorbidity Survey Replication Adolescent Supplement (NCS-A), a US faceto-face household survey of the prevalence and correlates of DSM-IV mental disorders. The survey was based on a dual-frame design that included 904 adolescent residents of the households that participated in the US National Comorbidity Survey Replication (85.9% response rate) and 9244 adolescent students selected from a nationally representative sample of 320 schools (74.7% response rate). After expositing the logic of dual-frame designs, comparisons are presented of sample and population distributions on Census sociodemographic variables and, in the school sample, school characteristics. These document only minor differences between the samples and the population. The results of statistical analysis of the bias-effi ciency trade-off in weight trimming are then presented. These show that modest trimming meaningfully reduces mean squared error. Analysis of comparative sample effi ciency shows that the household sample is more effi cient than the school sample, leading to the household sample getting a higher weight relative to its size in the consolidated sample relative to the school sample. Taken together, these results show that the NCS-A is an effi cient sample of the target population with good representativeness on a range of socio-demographic and geographic variables.

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